1. Field of the Invention
The present invention relates to an image forming apparatus which forms an image on a transfer material by use of an electrophotographic system, and an exhaust mechanism for exhausting heat or the like generated in the image forming apparatus to the outside.
2. Description of the Related Art
In an image forming apparatus in which an electrophotographic system is used, a fixing device which fuses a developer image transferred onto a transfer material to fix the image onto the transfer material, a power supply device which supplies a power to an electric equipment disposed in the apparatus and the like are mounted. The fixing device includes a heating roller which is heated at several hundreds of degrees to fuse a developer.
When other members disposed in the apparatus are heated by heat generated from the fixing device and the power supply device and accumulated in the apparatus without being exhausted to the outside, a problem occurs that the electric equipment malfunctions or that the characteristics of the toner change due to temperature.
For example, in Jpn. Pat. Appln. KOKAI Publication No. 5-11554 (U.S. Pat. No. 5,335,049), an image forming apparatus is described in which an exhaust mechanism is protruded from a main body frame, and an exhaust port can be maintained even in a case where a main body is disposed in the vicinity of a wall or the like or an object is disposed at the exhaust port. The apparatus will be described in detail. In the apparatus, a fan for exhaust is disposed in the apparatus, and a large number of slit-shaped exhaust ports are formed in the exhaust mechanism having a substantially spherical section. By this constitution, even when an object is placed at the exhaust ports, the exhaust ports are prevented from being completely closed, and can be secured.
However, when continuous image formation is instructed in the image forming apparatus, and a copying operation or the like is continuously executed, the temperature becomes very high in the apparatus. In this case, when an object is placed at the exhaust ports and is not moved, an exhaust performance degrades even in a state in which the exhaust ports are not completely closed. The heat in the apparatus is not sufficiently exhausted, and the temperature rises in the apparatus in some case. This causes a problem that the electric equipment disposed in the apparatus malfunctions or fails.